Computer analysis of the correlation between the activity of the masseter muscles during unilateral chewing in man
Hannam, A.G.
Electromyography and Clinical Neurophysiology 16(2-3): 165-175
1976
ISSN/ISBN: 0301-150X PMID: 964196 Document Number: 103570
Surface electromyography was used to record the electrical activity of the right and left masseter muscles in 10 subjects who performed unilateral chewing tasks. An on-line computer sampled and modified the data so that cross-correlation analysis could be carried out in 2 different ways, one expressing the association between the total responses and the muscles from bite to bite, and the other expressing the association between their contraction patterns within an average chewing stroke. It was also possible to demonstrate, by means of lagging techniques, any differences in timing of the 2 patterns of contraction. The total sample of subjects showed no significant difference as a group in the correlation between the muscles from bite to bite when chewing on either side. Individuals showed marked differences, indicating that depending upon the side used, the masseter muscles may vary in the degree to which their successive contractions are synchronous. In almost half the sample, the muscle contralateral to that on the side chewed upon started to contract first, while the remainder of the sample either did not show any evidence of a leading muscle, always led with the same muscle, or only showed a leading tendency when a particular side was used. The technique appears to provide a sensitive and quantitative method for comparing functionally related muscle groups.